Topic: Video game console development missing the mark

We all know that video game developers who decide to create a whole console will take a substantial financial loss. Instead of creating a system from scratch, why not make it upgradable? Nintendo ventured slightly into this territory with the N64 expansion pack. There is no reason why an upgradable system is impossible. Instead of selling a whole new system and control scheme, just maker a new graphics card. Make a port on the old system you could open, unplug the old card and install the new one. This could sharply drive down the costs of development and increase the life of an existing system. If it had been implemented on the wii for instance, you would flip the unit over, dislodge the chip set cover, pull out the chip and plug in the new one. The system will then download any os updates, you'd slap a decal on the system that says "Wii2" or whatever and voila! They could even partner with various retail outlets like GameStop or toys r us and they will install it for you if your uncomfortable doing it. New games will be clearly marked "Wii2" and placed seperately from the old Wii games as if it were a new system. Costs to both developer and consumer would be drastically reduced, and spending 500 bucks on a playstation 4 would be a thing of the past. Charge 100-150 and make the consumer know that your old system is now a completely new system!
There are only a few problems that I can see. One is disk space. Obviously a Wii disk is not sufficient memory for many HD games. A system would have to already have blu ray or better capabilities, so the wii analogy is perhaps not the best. Sony has already stated that it doesn't want to go all out like with the playstation 3, so this model would have worked beautifully on it.
The second problem is age of other components. I have an NES that still works great. I recieved it as a gift in 1987. I have only ever had to purchase a new AC adaptor to keep it running. Some game systems however (cough cough Xbox I'm looking in your general direction) have had overheating problems that companies would like to address with the launch of a brand new system.
Perhaps a compromise could be reached. Launch new models of a certain system only after a certain point with then new chipset. Mark the box Wii2, Playstation 4, or Xbox forever spinning in circles. In tandem, release the chipset option that will save those who wish to; money on their upgrade, and company money on additional units having to be created.
What are your thoughts? Thanks!